Napster has launched Napster To Go, a version of its online music subscription service based on Microsoft's latest DRM technology, 'Janus'.

The announcement follows Microsoft's release of the latest Windows Media Player 10 beta, which incorporates Janus, and includes Napster and other Windows Media-using music services in WMP 10's 'Digital Media Mall' storefront.

Of course, since WMP 10 is still in beta, so by necessity is Napster To Go, which is due to go live "later this Fall", presumably when Microsoft ships the finished version of WMP 10. At that time, Napster will ship version 3.0 of its own client app.

In preview or finished release, Napster To Go (NTG) provides songs that can be copied over to a Janus-compatible portable music player, such as Rio's Carbon or Creative's upcoming Zen Portable Media Center, but expect more to follow when WMP 10 is finished.

Hardware vendors hope Janus will boost the market for their players, by allowing their users similar freedoms enjoyed by iPod owners. Likewise, Napster and co. hope that hardware support will boost the demand for downloads from their music stores - now all competing with Microsoft's own, of course, as well as Apple's.

It doesn't come cheap, however. Napster's preview release of NTG costs $14.95 a month, compared to the regular $9.95 a month subscription. If the case for market demand for "tethered" deals - as Napster itself calls its subscription services - hasn't yet been made, it's certainly unclear whether consumers will be willing to pay even more a month simply for the right to copy files over to a portable player. Napster's shareholders may like it, but will its customers?

Napster claims its NTG pricing is provisional, final pricing having yet been determined. Like the existing subscription service, NTG will offer unlimited download volumes. ®